Board:tyan/s2892

Purpose:
Customize the system to allow me to play with memory mappings and large
devices. I wanted to minimize intermediate steps from LinuxBIOS to Linux to
minimize the areas of expertise I needed to develop. I also wanted to be
able to use the SATA drives as my boot drives.

Disclaimer:
There are several places where my solutions are not as elegant as I wished
them to be. Suggestions are welcome.

Current set up:
Tyan s2892
LinuxBIOS with Linux 2.6.18-tiny as a payload

I started by installing LinuxBIOS on the system and using FILO and Etherboot
to boot to a kernel. This allowed me to try the different payloads without
flashing every time.

and took out the graphical boot menu. I also modified
buildrom/skeleton/devices.txt to add lines for my hard drives. I just
copied the lines for sda and sda1 and made had hda1 hda2 and sda2. The
important thing is to make sure that the major and minor numbers are
correct.

I modified buildrom/skeleton/linuxrc so that the device files were created
earlier, /dev/null didn't become a text file, and my drives got mounted.

I then modified buildrom/skeleton/bin/boot.functions so that doboot() called
my script on the hard drive for the kexec. That's nice to avoid flashing
the BIOS for booting different kernels.

I downloaded Linux 2.6.18.1 (2.6.18-rc4 had some problems with SATA) and
patched it with the tiny patches that came with OLPC.
12-tiny-tiny-crc.patch fails, but was easy to apply by hand.

I configured the kernel to include support for ext2 and ext3, SATA, and IDE.

I ran make and copied the payloads from the buildrom/deploy directory to my
s2892 to be used. olpc-payload.elf.lzma (732K) is used for booting directly
from LinuxBIOS, and olpc-payload-uncompressed.elf (1.7M) was useful for
testing it with FILO and Etherboot.

I'd like to go one step further and use a 64-bit kernel so that any changes
I make to the kernel only need to be made once. Looking at mkelfimage, it
looks like the 64-bit file format is not supported. It might be a simple
change, but I don't know how to do it.

Since I couldn't figure out how to make LinuxBIOS do without the Fallback
image, I configured it to have a zero size payload.

If I could get rid of the fallback it would make room for the 64-bit kernel
(50K bigger than the 32-bit kernel). Then I'd just need to modify
mkelfimage and I'd be almost there :) I guess I could take out pciutils to
make up most of the difference (44K), but I like having them there for
debug.